Yellow-flowered lucerne: properties and influence on performance and reproduction of ewes

Conception rates and prolificacy of Finnish Landrace ewes fed yellow-flower ed lucerne (Medicago falcata L.) pasture and silage prior to and during the mating period were compared with those of control ewes fed timothy (Phleum pratense L.) - meadow fescue (Festuca pratensis Huds.) pasture and silage. Ewes grazed pasture for four weeks and received their respective silage fo r 10 weeks indoors. Dry matter (DM) intake of lucerne silage was higher tha n that of grass silage (1.77 vs. 1.40 kg DM day(-1)). Timothy-fescue grass and silage analysed by a new modified method did not contain detectable amo unts of plant oestrogens. In fresh and preserved lucerne, the amount of cou mestrol was only moderate varying from zero to 59.5 ppm DM. Ewes fed lucern e received higher amounts of plant oestrogens than those on control feeding , but no differences in conception rate or lambing performance were found b etween the groups. However on lucerne, ewes conceived five days earlier (P= 0.03) than control animals. Prolificacy of lucerne and control fed ewes ave raged 3.13 and 3.19 lambs/ewe (P=0.76), respectively. There were no ewe hea lth problems. The results suggest that the intake of yellow-flowered lucern e is good and the level of plant oestrogens has no detrimental effects on r eproductive performance of adult Finnish Landrace ewes.